If you talk you a domain registrar like GoDaddy or Network Solutions, they'll make you believe that every domain extension (.com, .net, .us, , .biz, .tv, .org, .nz, etc.) should be locked up to "keep you safe". While there is some truth to this, it's not the whole truth.

The basics are this. It depends on your company name and whether you domain name is related to your company name or is it related to what you do.

The Company Name - Generic

RJS Consulting? - RJSConsulting.com

A very generic business name. Only one URL is necessary. There are probably hundreds of RJS companies in the world. If you have the .com extension you want or something that works well and is easily remembered by customers, you don't need to capture any other domain extensions. It would be a waste of money.

The Company Name - Specific

Example One - Mason Fire Protection Inc. - MasonFireProtections.com

This business name is very specific and if a competitor or similar business has this, it could cause some confusion. Now do you need every domain extension in this case? You do not. However from a legal standpoint, it's important to capture .com .net and .us to establish that you have a true claim to this and to discourage others from interfering.

Example Two - Custom Headlights Inc. - CustomHeadlights.com

This domain is directly related to your business and competitors could take other domains and try to create confusion or take market share from you. In this it would be appropriate to capture .com, .net, .us, and .biz. The rest of the domain name extensions beyond is not necessary.

And Finally the big question. Is there ever a case where I need to purchase every extension of my domain name? No. If your business name and domain ownership of several extensions are the same or similar, you are in a good position. Don't waste your money.